WASHINGTON (AP) — House Republican freshmen are caught between rock-solid fiscal conservatism and a political hard place.

The class of 2010 that lifted the GOP to its comfortable House majority pushed the leadership to a vote Tuesday on legislation that would slash spending by trillions of dollars and require a balanced budget constitutional amendment in exchange for an increase in the nation's borrowing limit.

It was a hard-won victory consistent with the campaign promises that helped get the 87 GOP members elected in November.

But the measure's chances are poor in the Senate, setting the stage for a backup plan from congressional leaders that would allow the government to avoid an unprecedented default on Aug. 2.

That would force freshmen to back an increase in the $14.3 trillion debt ceiling, and several constituents are telling them not to do it.

"I'm actually being accused of selling out back home," Rep. Mick Mulvaney, R-S.C., said in an interview. "Some folks don't want to raise it under any circumstances. I tried to explain to them that this is the one chance to actually change Washington, so most folks will come around after we have that discussion."

The former state lawmaker who ousted the chairman of the House Budget Committee, Democrat John Spratt, said he was hearing from the "extreme right wing."

Solid backing of tea partyers helped propel several freshmen to Washington, boosting the candidacy of citizen-lawmakers such as car dealers, pizza shop owners, farmers and businessmen. The Tea Party Express on Tuesday threatened GOP primary challenges to Republicans who support Senate Minority Leader Mitch McConnell's alternative plan to give President Barack Obama the power to order an increase in the debt limit of up to $2.5 trillion over the coming year.

Another tea party group warned about the "disease of Republican compromise" infecting Washington and ceding to Obama's demands.

On the other side, freshmen Republicans face pressure from McConnell's sober warning that failure to raise the debt ceiling could be blamed on Republicans and ensure another term for Obama in 2012. Separately, House Republicans are hearing from business owners who echo the dire warnings from economists and financial analysts about the ramifications of a government default.

The votes in the coming days could have widespread implications for GOP freshmen next year, determining whether they get a challenge from within the party in a primary or have to answer for their decisions in the general election.

A new CBS poll found the public had soured on both Obama and congressional Republicans in the debt talks, but the GOP got lower marks than the president.

Frustrated with the president, about 20 freshmen took a bus to the White House on Tuesday to press Obama to detail his deficit-cutting plan.

"We don't care about re-election. We're here to do the work and we're asking the president, put it in writing, let's debate it," said Rep. Tom Reed, R-N.Y. "We thought it was so important, we came here physically."

Scoffing at claims of economic calamity if the debt ceiling isn't raised, Rep. Mo Brooks, R-Ala., said such statements are "absolutely wrong" and "misleading the American people." Brooks argued that the government would still have enough revenue to pay its creditors.

"This is Barack Obama's debt, this is Barack Obama's debt ceiling," Brooks said, adding that Obama had been "AWOL" on the issue.

Neither Obama nor a White House official met with the group and they returned to the Capitol.

Rep. Vicky Hartzler, R-Mo., who owns an agriculture business with her husband, said business owners, bankers and others in her district are pushing for deep spending cuts.

"They understand this overwhelming debt is hurting our economy and impeding job creation so we need to rein in this runaway spending, get control of our debt so that we can grow and create jobs," Hartzler said in an interview.

The Missouri congresswoman said she hasn't heard specifically from tea partyers, but added, "my district was tea party before tea party was cool."

It's unclear how freshman Republicans will vote in the coming days if faced with a possible compromise that includes raising the debt limit.

Hartzler said she would vote "no, at this point." Mulvaney pointed out that for lawmakers who backed the so-called cut, cap and balance bill in the House "there's a lot of latitude in some of those things."

The GOP freshmen are hardly monolithic on budget issues. In April, most of the 87 relented and voted for the compromise worked out by Obama and House Speaker John Boehner to keep the government running. Sixty of the 87 supported the package that included spending cuts of $38 billion, far less than the $61 billion many had pushed for, while 27 of the freshmen opposed it.

In February, House Republican freshmen led the charge in voting to cancel $450 million for an alternative engine for the next-generation F-35 fighter plane, going against Boehner and other House GOP leaders.

Whatever the spending cuts in any deal, Mulvaney offered an assessment of Washington after more than a half year in office.

"There's more smoke and mirrors in this town than a Barnum and Bailey circus when it comes to counting," he said.